Merge branch 'improve-releases-dev-23a' into 'releases/dev-23a'

Update releases branch with changes from  19/06 discussion

See merge request !36

spack_setup.sh

@@ -6,8 +6,8 @@ set -E -o pipefail
 # ---- configuration variables ----
 spack_git='https://github.com/mpsd-computational-science/spack.git'
 spack_git_ssh='git@github.com:mpsd-computational-science/spack.git'
-spack_branch='mpsd/v0.19'
-system_compiler="gcc@10.2.1"
+spack_branch='mpsd/v0.19_dev-23a'
+system_compiler="gcc"
 generic_arch="x86_64_v2"
 # default: spack cache is one level above pwd
 spack_cache=`realpath ../mpsd-spack-cache`